The use of water-soluble pouches for different applications, especially for cleaning applications, has become increasingly popular. Among many other advantages pouches avoid the contact of the user with the cleaning composition which may contain bleach and/or other irritant substances. Single compartment detergent pouches are known in the art and are sold commercially. WO 02/14460 discloses pouches having a crushing resistance of at least 1 N at 23° C.
Multi-compartment detergent pouches containing compositions in different physical forms in separate compartments are also known in the art. WO 02/42400, WO 02/42401 and WO 02/42408 disclose a dual-compartment pouch wherein one of the compartments contains a liquid composition and the other compartment contains a composition in powder form.
A problem found in both single and multi-compartment pouches but especially in dual-compartment pouches having compositions in different physical forms is that the pouches can lose strength with time, leading to the risk of rupture under typical transport and storage conditions. This problem can be especially acute in the case of pouches containing hygroscopic powders and other compositions prone to absorb water from the environment. Pouches are usually packed in a single container, therefore the rupture of one pouch will detrimentally affect the remainder of the pouches packed in the same container.
Thus an object of the present invention is to provide liquid containing detergent pouches of improved strength. Another object is to provide detergent pouches whose strength does not decrease considerably with time. A further object is to provide multi-compartment liquid/powder pouches wherein both the liquid and the powder compartment have excellent physical strength and storage stability.